Most of the carbon dioxide in the blood is transported as

Correct Answer: C

Rationale: The correct answer is C: bicarbonate ions. Carbon dioxide in the blood mainly combines with water to form carbonic acid, which dissociates into bicarbonate ions and hydrogen ions. The majority of carbon dioxide is transported in the blood as bicarbonate ions. This process occurs in red blood cells via the enzyme carbonic anhydrase. Choices A and D are incorrect as carbon dioxide mainly combines with water and does not remain as a solute in plasma or cytoplasm. Choice B, carbaminohemoglobin, is a minor way carbon dioxide is transported, where a small amount binds to hemoglobin, but the majority is transported as bicarbonate ions.

Correct Answer: C

Rationale: The correct answer is C: to remove pathogens and debris. Alveolar macrophages are specialized immune cells located in the lungs responsible for engulfing and clearing pathogens, debris, and foreign particles. This function helps maintain lung health and prevents infections. Rationale: 1. Alveolar macrophages are part of the immune system and act as the first line of defense in the lungs. 2. Their primary role is phagocytosis, engulfing and destroying pathogens and debris to protect the respiratory system. 3. Secreting pulmonary surfactant (choice A) is the function of type II alveolar cells, not alveolar macrophages. 4. While alveolar macrophages can secrete some antimicrobial proteins (choice B), their main function is phagocytosis. 5. Facilitating gas exchange (choice D) is the role of the alveoli and not specifically of alveolar macrophages. In summary,

Correct Answer: B

Rationale: The correct answer is B: paired arytenoid cartilage. These cartilages are triangular and play a crucial role in adjusting the tension and position of the vocal cords, thus affecting voice pitch and quality. The thyroid cartilage (A) is a large shield-shaped cartilage, the corniculate cartilage (C) is small and horn-shaped, and the cricoid cartilage (D) is a ring-shaped cartilage. These cartilages do not directly influence the vocal cords' tension and position.

Correct Answer: D

Rationale: The correct answer is D because the oropharynx contains both palatine tonsils (choice A) and lingual tonsils (choice B). Palatine tonsils are located on the sides of the oropharynx and lingual tonsils are located at the base of the tongue. Pharyngeal tonsils (choice C) are also known as adenoids and are located in the nasopharynx, not the oropharynx. Therefore, choices A, B, and C alone are incorrect. Choice D is correct because both palatine tonsils and lingual tonsils are present in the oropharynx.

Correct Answer: D

Rationale: To determine the correct oxygen flow for a simple face mask, you should increase it from the previous nasal cannula rate. As simple face masks deliver oxygen less efficiently, a higher flow rate is needed to maintain the same oxygen concentration. Moving from 3 L/min nasal cannula to a simple face mask, you should increase the flow to 6 L/min to ensure adequate oxygen delivery to the patient with chronic airflow limitation. Choices A and B are incorrect as decreasing or keeping the flow the same would not provide sufficient oxygen. Choice C is also incorrect as increasing it to 4 L/min may not be enough to compensate for the decreased efficiency of the simple face mask.